George Washington University Law School professor Jonathan Turley, a noted constitutional expert, explained the difference on Friday between President Barack Obama’s legal case involving lawsuits against Obamacare and President Donald Trump’s national emergency declaration.

“They’re using the case where I represented the House of Representatives against Obamacare. And we won. But this is not the same case,” Turley said on “Fox & Friends.

“What President Obama did was order the Treasury essentially to be opened up and to pay insurance companies. That’s a different type of funding.”

“What Trump is going to do is he’s going to use money that was appropriated by Congress. It just doesn’t have these tight conditions on them. That’s Congress’ decision to make. They can appropriate money and not put many conditions on.

“So it’s going to be a different fight,” Turley continued.

Turley predicted that POTUS Trump’s declaration would face challenges in court, and it is — the ACLU has promised to sue as has the state of California.

But Turley says Leftist groups and congressional Democrats opposed to the president’s declaration are going to lose on the merits of the case because Congress has already bestowed such powers on the Executive Branch.

“So there’s two issues here for the court,” said Turley.

“The authority, the source of the authority to declare the emergency and the source of the funds. On the source of authority, they will lose in a spectacular fashion because they gave this authority to the president (in 1976),” he added. “He and other presidents have virtually unfettered authority to declare an emergency.

“Remember, the president can start construction with the money Congress just gave him. And even if they knocked out one or two of these sources he still has plenty to go pretty far down that road,” Turley said.

The president himself essentially laid out the legal strategy that will be employed by his political opponents on Friday when he announced he would use an emergency declaration to secure funding for the border wall.

He said he believes he’ll be sued — most likely in the Leftist 9th Circuit, where he’ll lose the first few rounds — but will eventually prevail at the U.S. Supreme Court.

As we reported, there are currently 31 national emergencies, many in effect for decades. One of them was issued by President Jimmy Carter in response to the Iranian takeover of the U.S. Embassy in Tehran in 1979.